Instana tracer implementation

docs/configuration/tracing.md

@@ -4,7 +4,7 @@ The tracing system allows developers to visualize call flows in their infrastruc
 
 We use [OpenTracing](http://opentracing.io). It is an open standard designed for distributed tracing.
 
-Traefik supports three tracing backends: Jaeger, Zipkin and DataDog.
+Traefik supports four tracing backends: Jaeger, Zipkin, DataDog, and Instana.
 
 ## Jaeger
 
@@ -188,3 +188,41 @@ Traefik supports three tracing backends: Jaeger, Zipkin and DataDog.
     #
     prioritySampling = false
 ```
+
+## Instana
+
+```toml
+# Tracing definition
+[tracing]
+  # Backend name used to send tracing data
+  #
+  # Default: "jaeger"
+  #
+  backend = "instana"
+  # Service name used in Instana backend
+  #
+  # Default: "traefik"
+  #
+  serviceName = "traefik"
+  [tracing.instana]
+    # Local Agent Host instructs reporter to send spans to instana-agent at this address
+    #
+    # Default: "127.0.0.1"
+    #
+    localAgentHost = "127.0.0.1"
+    # Local Agent port instructs reporter to send spans to the instana-agent at this port
+    # 
+    # Default: 42699
+    #
+    localAgentPort = 42699
+    # Set Instana tracer log level
+    #
+    # Default: info
+    # Valid values for logLevel field are:
+    #   - error
+    #   - warn
+    #   - debug
+    #   - info
+    #
+    logLevel = "info"
+```